Rotary well drill



z 0' U z 22 8 ll. wig H #1 INVENTOR. mpsan ATTORNEY.

July 16, 1940.

L. THOMPSON ROTARY WELL DRILL Filed Feb. 3, 1938 LoDm'eL. 7170 Patented July 16, 1940 UNITED STATES ROTARY WELL DRILL Lonnie L. Thompson, Iowa Park, Tex., assignor to Thompson Tool Company, Inc., Iowa Park, Tex., a corporation of Texas Application'February 3, 1938, Serial No. 188,557

10 Claims.

This invention relates to improvements'in bits for rotary well drills and more particularly to the type employing rotatable toothed cutters.

Heretofore, the bits used to bore holes of large 5 diameter, would drift and wobble to such an extent as to make it very diflicult to get a hole started straight.

An object of the present invention is to control the direction of drilling, as by a pilot bit of 10 smaller diameter than the reaming or cutting bit. The pilot bit may be of any desired size and style and may be detachably secured to the lower end of the drill. Threaded connections are supplied at both the upper and lower ends of the rotary l5 drill, the upper connection permitting the bit to be coupled to the drill stem and the lower connection allowing the bit to be connected to the pilot bit.

Another object of this invention is to cut holes of larger diameter by the rotary drill than is cut by the pilot or guide bit.

Still another object of this invention is .to shield the toothed cutters of the rotary well drill bit for the purpose of holding the circulating fluid 25 in the bottom of the hole during the drilling operation.

While the drawing illustrates a preferred embodiment of the invention, it is to be understood that in adapting same to meet specific needs and requirements, the design may be varied and changes made in the minor details of construcion within the scope of the invention as claimed .rithout departing from the spirit thereof.

In the drawing:

Fig. 1 is a quarter section showing a pilot bit attached to the lower end of the drill bit;

Fig. 2 is a view similar to Fig. 1,- but taken at right angles thereto, with the pilot bit removed;

Fig. 3 is a bottom view of the drill bit;

Fig. 4 is an enlarged perspective view of a roller bearing detached showing a special lock therefor; and

Fig. 5 is a perspective view of a locking ring and bearing thrust plate that interflts with the a bearing body.

With more particular reference to the drawing, the numeral 6 represents the body of the bit which is preferably made of unitary construction. An externally threaded portion 1 is pro- 50 vided at the upper end of said body 6 to interflt with a regulation tool joint of a rotary drill stem for securing the drill thereto. An internally threaded connection 8 is provided at the lower end of the bit body 6 to provide for the attach- 55 ment of a pilot bit 9 or a guide stem.

An axial opening III is formed entirely through the body 6 permitting fluid to pass through the bit and some of the fluid to escape through lateral openings II to be directed against radial cutters I2 and I3. This fluid is circulated through 5 the drill stem by high pressure pumps and due to.the openings discharging directly against the faces of the cutters, the earth is continuously washed therefrom. Surplus circulating fluid is permitted to continue on through axial opening 10 III to discharge through openings ll of the pilot bit into the bottom of the hole. The body 6 has a skirt I5 which encloses the upper portions of the cutters I2 and I3 and forces the fluid to exhaust near the bottom of the hole upon which the cutters are operating.

The bit carries two separate and independent types of toothed cutters, the cutters of one type .being mounted upon horizontal shafts and are frustro-conical in shape, as shown at I2. These cutters I2 cut a bevel on the bottom of the hole which converges upwardly and inwardly, while the other cutters I3 are mounted on angular shafts I9 and have their cutting edges disposed substantially horizontally. Cutters I2 cut their width outward from the edge of the pilot bit hole and cutters I3 cut outwardly from the outer edge of the hole made by cutters I2, leaving a smooth clean wall 23 of the hole.

A roller bearing I6, having locking shoulder I1 thereon, forms a journal for each of the cutters I2 and I3. The body of this bearing cage I6 is almost a bearing flt with the inner bore of the cutter and interflts so closely (with a clearance of only .005") that foreign matter such as sand and rock cuttings are excluded from the rollers but it is of suflicient clearance to permit water or other liquid to enter around the bearings, thereby preventing heating and wear.

A shoulder I! on each end of the bearing cage I6 interlocks with a bearing thrust plate l8 or I8 at the outer andinner ends of each cutter. Whenthe cutter and bearing cage are assembled in the body, the bearing plates I8 and I8 are welded to the body 6 at points 22 to prevent the bearing thrust plates I8 and I8 and bearing cage from turning and causing wear on the shafts I9 and 20. The rollers in bearing I6 are preferably of the double row construction and interflt closely so as to prevent them from getting out 50 of alignment. The shafts I9 and 20 are welded at points 2I to hold the shafts against turning, but both the welds 2| and 22 are of such nature that they may be readily 'cut loose with a torch or chisel so as to facilitate disassembling the cut- F ters of the bit for the purpose of repairs or replacement. Bearing thrust plates I! prevent wear on the body and may be readily removed when they become worn and new plates inserted; By having auxiliary plates attached by tacking with a welding torch, it permits the bit body 0 to be used a number of times, as the, original machine work thereon will be as good as new, because the only points of wear will be on the thrust plates l8 and IS, the bearings l6, and the cutters l2 and II.

The cutters l3 will cut the hole 23 sufilciently large to permit free circulation between the out-.

side of the skirt i5 and the inner side of the hole.

This bit is particularly adaptable for enlarging a hole. To enlarge or ream, it is necessary only to screw a guide stem approximately the size of the hole into threaded connection 8. However, as shown in Fig. 1, the bit may be used to drill and ream at the same time and either a fish tall" or a rock bit may be used as a pilot bit, or the pilot may be removed and' the drill used without a pilot, if desired. I claim:

1. A rotary drill bit comprising a body having a surrounding wall with the lower edge thereof arranged in circular formation concentric with the body, and means mounting one or more outters within the surrounding wall with the major portion of each cutter above the lower edge of said wall, said body having means for directing fluid onto the cutter or cutters. I

2. A side wall reaming drill bit comprising a body having a surrounding wall with the lower edge thereof arranged in the form of a circle concentric with the body, said body having an axial passageway therethrough andhaving lateral recesses in the periphery thereof from beneath the circular lower edge of the wall, cutters, and means for mounting the cutters within the recessesf with the major portion of each cutter above the lower edge of said wall, said body having means for directing fluid from the axial passageway laterally onto the cutters.

3. A rotary drill bit comprising a body portion having one or more radially extending shafts, a cutter on each shaft, an anti-friction bearing cage for said cutter, and a thrust plate fixed to the body separate from the cage and having interlocking connection directly with the cage and holding the same against turning relative to the shaft.

4. A rotary drill bit comprising a body portion having a plurality of radially extending shafts, a cutter journaled on each shaft, a roller bearing cage joumaling the cutter, and a thrust plate fixed to the body separate from the cage and having interlocking connection directly with the bearing cage for holding said cage against turning relative to the shaft.

5. A rotary drill bit comprising a body portion having a plurality of radially extending shafts, a cutter journaled on each shaft, a roller bearing cage joumaling the cutter, and a thrust plate separate from the cage and having interlocking connection directly with the bearing cage for holding said cage against turning relative to the shaft, said thrust plate being removable from the body for disassembly and being normally fixed to the body.

6. A rotary drill bit comprising a body portion having a plurality of radially extending shafts carried thereby and carrying cutters, said body portion having outer and inner portions-embracing each cutter, each shaft extending in a hole entirely through the outer portion and only partway through the inner portion, and each shaft being removably fixed in the body portion, a roller bearing assembly interposed between the shaft and cutter and having a cage, a removable thrust plate at an end of the assembly separate therefrom and having interlocking connection directly with the cage and fixed to the body portion for holding the cage against tuming relative to the shaft.

7. A rotary drill bit comprising a body portion having a recess therein, a cutter shaft extending transversely of said recess, a bearing assembly surrounding said shaft, a cutter rotatably mounted on said bearing assembly,'said bearing assembly having a polygonal-shaped enlargement on an end thereof, and bearing thrust plate fixed to the body portion and fitted over said enlargement holding the bearing assembly against turning.

8. A rotary drill bit comprising a body portion having a recess therein, a cutter shaft extending transversely of said recess, an anti-friction bearing assembly including a cage surrounding said shaft, a cutter rotatably mounted on said bearing assembly, said bearing assembly having a polygonal-shaped enlargement on an end thereof, and a bearing thrust plate flxed to the body portion and fitted over said enlargement holding the bearing assemblyagainst turning relative to the shaft.

9. In a rotary drill bit of the type having a pilot at the lower end thereof, a body portion having a plurality of cutters spaced at intervals therearound, and'means journaling said cutters on the body portion for rotation about axes one of which is' approximately at a right angle to the axis of the body portion and another of which is at an acute angle, appreciably smaller than a right angle to the axis of the body portion.

10. In a rotary drill bit of the type having a pilot at the lower end thereof, a body portion having a plurality of cutters spaced at intervals therearound, and means joumaling said cutters on the body portion for rotation about axes one of which is approximately at a right angle to the axis of the body portion and another of which is at an acute angle, appreciably smaller than a right angle to the axis of the body portion, said inclined axis cutter having the cutting edge thereof projecting outwardly appreciably be- .yond the cutting edge of the right angle axis cutter. 

